Pilot scale of Spirulina production by nutrient management approach

Spirulina (Arthrospira platensis) has been widely used in various commercial products, including food and feed supplements and cosmetics. The minimization of production cost while maintaining environmentally friendly production process has been considered. Zarrouk’s medium, a standard medium, was successfully modified and tested on a lab scale. This research aimed to study the utilization of the modified medium (mainly reducing NaHCO₃ and NaNO₃ by 52% and 66% from the standard medium, respectively) for a pilot-scale volume of 3,000 L with different cultivation management by comparing the use of fresh medium versus recycling medium after algae separation. This study was conducted during March – April 2023, with an average highest light intensity of about 1775 ± 410 mol photons m^-2 s^-1, and average maximum ambient and culture temperatures about 39 ± 2 °C and 35 ± 1 °C, respectively. The results demonstrated that the production of Spirulina biomass using a recycling medium was lower than the control culture in fresh medium by 36.7%, but both cultures exhibited similar biochemical compositions (protein 69-71%, carbohydrates 23-24%, and total fatty acids 6.9-7.0% of dry weight). However, the chemical and water costs reduced by 49.2% compared to the control. Therefore, cost reduction through recycling culture medium is of further interest for maximizing productivity and minimizing production costs in the future.